Crudes (whether in the form of crude oils, or solid or semi-solid hydrocarbons such as bitumen) that have one or more unsuitable properties that do not allow the crudes to be economically transported, or processed using conventional facilities, are commonly referred to as “disadvantaged crudes”. Disadvantaged crudes may have a high viscosity that renders the disadvantaged crude undesirable for conventional transportation and/or treatment facilities. Disadvantaged crudes having high viscosities, additionally, may also include hydrogen deficient hydrocarbons. When processing disadvantaged crudes having hydrogen deficient hydrocarbons, consistent quantities of hydrogen may need to be added to inhibit coke formation, particularly if elevated temperatures and high pressure are used to process the disadvantaged crude. Hydrogen, however, is costly to produce and/or costly to transport to treatment facilities.
Conventional methods of reducing the high viscosity of the disadvantaged crude include contacting the disadvantaged crude at elevated temperatures and pressure with hydrogen in the presence of a catalyst. Deposits formed during processing may accumulate in the larger pores of the catalyst while viscosity and/or other properties are reduced by contact of the feed with the active metals in the smaller pores of the catalyst that the deposits and/or large compounds contributing to viscosity can not enter. Disadvantages of conventional catalysts are that they require significant amounts of hydrogen in order to process the hydrogen deficient hydrogens and the larger pores of the catalyst become filled. Thus, the activity of the catalyst is diminished and the life of the catalyst is reduced.
It would be desirable to have a method and/or a catalyst for reducing the viscosity of disadvantaged crudes at elevated temperatures and minimal pressures for a prolonged period of time.
U.S. Pat. Nos. 6,554,994 to Reynolds et al., 6,436,280 to Harle et al., 5,928,501 to Sudhakar et al., 4,937,222 to Angevine et al., 4,886,594 to Miller, 4,746,419 to Peck et al., 4,548,710 to Simpson, 4,525,472 to Morales et al., 4,499,203 to Toulhoat et al., 4,389,301 to Dahlberg et al., and 4,191,636 to Fukui et al. describe various processes, systems, and catalysts for processing crudes and/or disadvantaged crudes.
U.S. Published Patent Application Nos. 20050133414 through 20050133418 to Bhan et al.; 20050139518 through 20050139522 to Bhan et al., 20050145543 to Bhan et al., 20050150818 to Bhan et al., 20050155908 to Bhan et al., 20050167320 to Bhan et al., 20050167324 through 20050167332 to Bhan et al., 20050173301 through 20050173303 to Bhan et al., 20060060510 to Bhan; 20060231465 to Bhan; 20060231456 to Bhan; 20060234876 to Bhan; 20060231457 to Bhan and 20060234877 to Bhan; 20070000810 to Bhan et al.; 20070000808 to Bhan; 20070000811 to Bhan et al.; International Publication Nos. WO 2008/016969 and WO 2008/106979 to Bhan; and U.S. patent application Ser. Nos. 11/866,909; 11/866,916; 11/866,921 through 11/866,923; 11/866,926; 11/866,929 and 11/855,932 to Bhan et al., filed Oct. 3, 2007, are related patent applications and describe various processes, systems, and catalysts for processing crudes and/or disadvantaged crudes.
U.S. patent application Ser. No. 11/866,926 describes in Example 24 a catalyst that includes 0.02 grams of silica-alumina and 0.98 grams of alumina per gram of support, nickel and molybdenum. The catalyst has a median pore diameter of 155 Å, with at least 60% of the total number of pores in the pore size distribution having a pore diameter within 28 Å of the median pore diameter and a surface area of 179 m2/g. Contact of a hydrocarbon feed with the catalyst and hydrogen at a temperature of 410° C. and a pressure of 3.8 MPa produces a crude product that has a reduced viscosity as compared to the hydrocarbon feed with a hydrogen consumption of 35 Nm3/m3. The distribution of pores in the pore volume of the catalyst is not discussed in Example 24. In Example 26, the catalyst includes an alumina support, alumina oxide fines, and molybdenum metal. The catalyst has a median pore diameter of 117 Å and a bimodal distribution of pore diameter size of pores in the pore volume. Contact of the hydrocarbon feed at 400° C. and 3.8 MPa produces a crude product that has a reduced viscosity. Hydrogen consumption was not discussed for the process using the catalyst of Example 26.
International Publication Nos. WO 2008/016969 and WO 2008/106979 to Bhan describe catalysts and methods of using the catalyst to produce hydrocarbon products having reduced pitch, sulfur, and MCR as compared to the initial hydrocarbon feed. The catalysts described in Examples I and III include a support having 2% silica in 98% alumina, and catalytically active metals molybdenum and nickel. The catalysts have median pore diameters of less than 100 Å and surface areas ranging from 133.5 m2/g to 332 m2/g. The hydrocarbon products produced by contact of a heavy hydrocarbon with the catalysts at temperatures of 400° C. and pressures of 1900 psig (about 13 MPa) have reduced pitch and sulfur content as compared to the initial hydrocarbon feed. These publications do not discuss reduction of viscosity at minimal pressures with minimal hydrogen consumption.
It would be advantageous to be able to convert a hydrocarbon feed having a high viscosity, and therefore a low economic value, into a crude product having a decreased viscosity by contacting the hydrocarbon feed with minimal hydrogen consumption. The resulting crude product may, thereafter, be converted to selected hydrocarbon products using conventional hydrotreating catalysts.
In addition it would be advantageous to have a catalyst for carrying out the conversion of the hydrocarbon feed with a long useful life.